<style type="text/css">
#descdiv{
overflow: hidden;
height: 60px;
border: 1px solid red;
}
#descdiv p{
height:30px;
margin:0;
/* The shadow of the text will be inside the overflow-hidden but the text it self will not.
   This causes the text to be drawn even when it's outside of the clip*/
text-shadow: #fff 1px -1px 2px;
}

</style>

<div id="descdiv">
<p class="um_desc">&nbsp;</p>
<p class="um_desc">&nbsp;</p>
<p class="um_desc">sed diam nonummy nibh</p>
</div>

